This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
Pypilot added to existing NMEA 0183 nav instruments
Our generic NMEA 0183 nav instruments work just fine, but the LCD displays are "sunburned" and almost unreadable. Openplotter2 + OpenCPN 5.2 on RPi4 newly installed and working well. Now I need to drive the existing, working, autopilot (fluxgate compass, rudder angle sensor, linear drive). I'm assuming Pypilot can do the job. What do I need to do to make this work? Serial NMEA (APB) connection for data output from RPi4 back to nav instruments? Or does Pypilot directly accuate the linear drive?
pypilot directly actuates the linear drive, it doesn't actuate the motor via nmea0183, this is a level above the autopilot.

For example opencpn can send nmea0183 to pypilot to command a course. nmea0183 defines courses and so pypilot can follow for example. Not sure exactly what you are trying to achieve.
Thanks Sean, that's helpful. Physically, the output to the linear drive comes off the mpu9255?
(2020-09-15, 12:30 AM)SaltyPaws Wrote: Thanks Sean, that's helpful. Physically, the output to the linear drive comes off the mpu9255?

The linear drive is coupled with a motorcontroller and a arduino (the rudder position and several temperatures are also measured here).

The 925x is connected to an I2C bus to a Pi running the pypilot scripts.
The Pi will mostly work with tinypilot or openplotter as operating system.
This Pi also makes the connection to the NMEA network.

If you cut the power to the linear drive to preserve energy you can power off the arduino while the IMU data is still available for the NMEA network.

If you forward the IMU data from the tinypilot via SignalK to an NMEA2000 network you might want to tinker with the output a little.
Too many updates and the output is ever changing and practically unreadable.
Too little updates and the display might show blank values (you could use retransmits if necessary).

But the last part is most probable SignalK and not pypilot (or kplex or some other 0183 mux if you don't use SignalK).
My apologies for not being as quick with this. I have the RPi4 running openplotter. I have NMEA RSA sentences. What additional hardware do I need to make this work?
Motorcontroller with arduino:
(or something similar)

Connecting the mpu925x to the pi check the pi header and connect SCL / SCA / GND and depending on the MPU925x solution either 3.3V or 5V.

Use the OpenPlotter PyPilot and I2C plugins to configure the MPU (first the pypilot, second the i2c to connect the mpu to signalk).
I think you will find more infromation on the OpenPlotter part of the forum for the MPU925x connection.
sorry, the existing autopilot hardware and nmea data cannot be used by pypilot.

You need inertial sensors (recommend mpu9255) on i2c of the raspberry, and a pypilot motor controller which connects over the hardware serial port. All of these connections can be made on the first 10 pins of the header.

It is optional to wire buttons, displays and even an arduino-based RF receiver for wireless remotes to the other pins.
Thank you Sean. My linear drive draws approximately 7 amps (nominal 12v) while at anchor. Guessing even more while underway. What would you suggest for a motor controller in this 100watt situation?
hmm.... Maybe the regular controller works, for a while, but could eventually overheat.

I used to supply a controller with much higher power output in a metal enclosure but this took up all of my time assembling these so I discontinued it. It was not feasible to produce in quantity and since then I have lost at least 5-6 orders (but I need to sleep)

I have ordered prototypes for a high power controller to replace it. The quality is not the same but hopefully it will do the job and I will be able to make a lot of them. I expect to receive them in a few weeks and if they manage to supply 20 amps continuous without increasing in temperature more than 10C in a steady state, they will pass the requirement, otherwise I have to modify the design and try again. These also have switching regulators to hopefully drop the 15ma standby current down to 3-4 milliamps.
Perhaps this is where I can use my existing hardware as the motor controller?

Forum Jump:

Users browsing this thread: 1 Guest(s)